I've had one specimen of Helleborus orientalis for a whole lotta years now, in part shade and humusy soil. (Basically, woodland conditions are what they favor.) It's evergreen, with darkish purplish flowers in spring. Have also had a hybrid called 'Red Mountain' for a while (this will be its second winter, I think).
I figured last year that I needed to expand my collection and added some others, but I don't recall the species right now.
Anyway, don't be misled by that zone 4-6 stuff. I know gardeners are growing quite a few different species... in zone 3 Calgary, at least.

I planted three two years ago, one "Royal Heritage" (i think), rated zone 5 and two "Niger", rated zone 3. All came back last summer, though not overly vigourously. The two Nigers had disappeared by the middle of the summer, and i'm anxious to find out if they were just lurking underground and will come back this spring. I love hellebores and definitely need more - one of these years! :)

Thanks Lori, that's what I was wanting to know. I suspected they could be grown here but I don't know anyone who grows them. I will keep an eye out for H. orientalis if I can find it. Does it increase or decrease particularly? When you say you have had one specimen for many years I'm imagining it staying the same. And do you mulch it for the winter?

Thanks Marcia too, we posted at the same time. Perhaps the species is a little more dependable...

I wanted to thank you for milk jug advice too I just forgot on the WS thread :-) I'm not shunning you!

LOL No prob! And good luck with the hellebores!

I tried H. niger years ago, didn't make in pass one winter, althou like many other plants that died back then, the poor soil conditions and drought was the main factor, so if and ever I go to Holes, I'd like to try again.

My old plant has increased modestly over the years... having said that, though, it would be an embarrassment compared to west coast specimens of the same species that are 3' tall and wide! But all things are relative, and it's a decent-looking, healthy plant...would probably perform a little better if I fed it compost every year...
I don't mulch anything.

I think Helleborus niger is pickier than H. orientalis. One thing to note is that they are slow to establish and don't like to be moved. It took 4-5 years in the ground before my Helleborus orientalis began to bloom.

I've had Helleborus niger for about 2 years now, and it only got 1-2" tall last year. I don't...think...that my Helleborus orientalis was quite that slow to establish, but hopefully it will do a better this year. We'll have to see. I got both of mine from Jung Seeds in the USA.

Sharon

I tried a couple back up north several years ago (the 'Christmas Rose'?) but they didn't do very well for me and died over the winter each time I tried. :-[ Pictures of the flowers were very inticing so I had to try to grow it. After trying unsuccessfully twice I moved on to other plants...